Just one thing, I often solve one of these before I go to bed, and then when I get up in the morning, someone else has started one and I've missed out on posting a new one.. .Is my timezone difference being taken advantage of?

Ah, that's probably because I've been ill for several days now, Alex - I had a bad cold before I started getting this sleepy-bug....And Rob has been kindly keeping puzzles going so I don't go out of my mind having to rest so much.